Announcements

Job offersmore »

Tweeting Growers

Top 5 - yesterday

Top 5 - last week

Top 5 - last month

Exchange ratesmore »




Photosynthetic responses of leafy veg to irradiance and CO2 concentration

In a new study, the impact of irradiance (0–1200 μmol·m−2·s−1) and carbon dioxide concentration (CO2; 50–1200 ppm) on kale (Brassica oleracea and B. napus pabularia; three cultivars), Swiss chard (chard, Beta vulgaris; four cultivars), and spinach (Spinacea oleracea; three cultivars) photosynthetic rate (Pn; per area basis) was determined to facilitate maximizing yield in controlled environment production.

Spinach, chard, and kale maximum Pn were 23.8, 20.3, and 18.2 μmol CO2·m−2·s−1 fixed, respectively, across varieties (400 ppm CO2). Spinach and kale had the highest and lowest light compensation points [LCPs (73 and 13 μmol·m−2·s−1, respectively)] across varieties.

The light saturation points (LSPs) for chard and kale were similar at 884–978 μmol·m−2·s−1, but for spinach, the LSP was higher at 1238 μmol·m−2·s−1. Dark respiration was lowest on kale and highest on spinach (−0.83 and −5.00 μmol CO2·m−2·s−1, respectively). The spinach CO2 compensation point (CCP) was lower (56 ppm) than the chard or kale CCP (64–65 ppm).

Among varieties, ‘Red Russian’ kale Pn saturated at the lowest CO2 concentration (858 ppm), and ‘Bright Lights’ chard saturated at the highest (1266 ppm; 300 μmol·m−2·s−1). Spinach Pn was more responsive to increasing irradiance than to CO2. Kale Pn was more responsive to increasing CO2 than to irradiance, and chard Pn was equally responsive to increasing CO2 or irradiance. Implications and limitations of this work when “upscaling” to whole-plant responses are discussed.

Access the full study at HortScience.

Publication date: 7/21/2017

 


 

Other news in this sector:

8/18/2017 Which wavelengths of light are the most effective in photosynthesis?
8/17/2017 How to light your vining crops
8/17/2017 UK: Vertical farming a breeding ground for innovation
8/17/2017 Cravo shares results of Mexcian trials
8/16/2017 Response of hot pepper yield to irrigation water salinity
8/14/2017 Ireland: €24 million available under European Innovation Partnerships Initiative
8/11/2017 These fibre pads claim to store and release ethylene on demand
8/11/2017 Chinese astronauts use the WET Sensor to help grow lettuce in space
8/11/2017 Horticulture NZ responds to freshwater discussion: “Let’s not do this”
8/10/2017 "Taxing water an issue for us all"
8/10/2017 USDA no longer speaks about "Climate Change"
8/10/2017 Combining downward and upward lighting improves plant growth
8/9/2017 Dr. Kubota's video lectures on photoperiod and CO2 now available at Urban Ag News
8/9/2017 LED Grow Book second edition now available
8/9/2017 UK: Survey to understand poor tomato pollination by native bumblebees
8/7/2017 NatureSweet to boost crop yields with new camera technology
8/7/2017 LumiGrow releases LED Growers’ Guide for Vine Crops
7/21/2017 US (FL): $3 million grant helps researchers look for new growing locations
7/21/2017 Production potential generates interest in Dutoli
7/21/2017 Cucumbers in space provide insights on root growth